If you are starting using a SLR camera or planning to do so, this post is a collection of introductory tips that might help you getting started.

For the record, I’m an amateur photographer addicted to sunsets, sea and landscapes.

Kudos to my brother who taught me the first steps.

Automatic vs Manual

The automatic mode is a great way to get started with your reflex camera. But you only take advantage of the full features of your camera, and thus increase the quality of your photos, as soon as you start getting away from it and moving towards the manual mode.

It doesn’t need to be a drastic change, as most cameras offer a way of partially setting some parameters manually and let the camera algorithms chose the remaining ones.

The Exposure Triangle

Exposure is the amount of light that reaches the camera sensor to create the photo. It is comprised of three factors:

  • Aperture
  • Shutter speed
  • ISO


Inside the lens there exists a diaphragm that opens and closes to control the amount of light that are allowed to get in. In photography terminology, that is represented with the following format:


The above mentioned number is a ratio between the focal length and the aperture diameter. The lower the value, the greater the aperture, resulting on more light reaching the sensor. This means that the picture will come out lighter.

That said, f/1 means that the aperture diameter is equal to the focal length. If we set the apeture to f/8, less light will reach the sensor.

Aperture Priority (Av) is a partial automatic mode usually present in the reflex cameras that allows the user to control the aperture value and leave the other settings to be set automatically.

Shutter speed

Right after the sensor, the shutter prevents the light from reaching the sensor until the moment the shutter button is pressed. When the button is pressed, that shutter opens and closes after a configurable amount of time. The shutter speed is related to the amount of time the shutter takes between opening and closing. In photography terminology, that is represented with the following format:


The number is a value, in seconds, representing the amount of time the shutter is opened for receiveing light. The less number the quicker the shutter will close (e.g. 1/100s makes the shutter close quicker than 1s).

Shutter Priority (Tv) is a partial automatic mode usually present in the reflex cameras that allows the user to control the shutter speed value and leave the other settings to be set automatically.


The ISO represents the sensitivity to the light. It represents the ability for the sensor to record the light being received. The ISO allows the user to record more or less light. It is represented with the following terminology:


The lower the number, the less light will be recorded (e.g ISO100 records less light than ISO600).

The Stop

Now that you are aware of the fabulous exposure triangle, the next concept to introduce is the stop. For each of the settings of the exposure triangle, there exists a standard scale. A stop represents a position in the scale.

Each time we are moving in the scale, no matter the direction, we are moving one stop.

Please note that some cameras do not strictly follow the standard scales, and introduce partial stop values in between the standard values. In that case, moving one value in one of the settings might not be necessarily moving one stop (depending on how many values lie between the standard values).

Aperture standard stops

Works in a way pretty much similar to the fibonnaci sequence. The first two numbers are fixed (f/1 and f/1.4), all the remaining values are the value at two stops behind multiplied by 2.

f/1 <-> f/1.4 <-> f/2 <-> f/2.8 <-> f/4 <-> f/5.6 ...

Shutter speed standard stops

The number is almost always multiplied or divided by 2, except some particular cases (e.g. 1/8 <-> 1/15).

1s <-> 1/2s <-> 1/4s <-> 1/8s <-> 1/15s <-> 1/30s <-> 1/60s ...

ISO standard stops

The number is multipled or divided by 2 if we move forward or backward, respectively.

ISO100 <-> ISO200 <-> ISO400 <-> ISO800 ...

It is important to be aware of the stops, instead of randomly moving the wheel. Being fully aware of how the stops in every situation, makes us better prepared to take the right picture at the right moment.

Combining the settings

All the mentioned settings of the exposure triangle are combinable in order to construct the picture we want. So if we need to reduce the aperture for some reason (e.g. taking advantage of a secondary effect explained below), that will reduce the amount of light reaching the sensor. But we can make it up by changing another setting, like ISO. That might bring some undesirable secondary effect as well, so it’s important to understand the meaning of each parameter.


f/11 ; 1/100s ; ISO 400
f/11 ; 1/200s ; ISO 800

The change on each setting may bring secondary effects that might be desirable or not, so it’s important to understand them right. Let’s take an example with the following picture.

Aperture secondary effects

Having a low aperture value does not only increases the amount of light reaching the sensor, it also reduces the field of depth, making the background a lot more blurry. That might be intended, but might be not as well. The following example was taken with a low aperture value.

Depth of Field

If the goal is to get a shaped background as well, we will need to increase the aperture value, but that will take more light to the sensor. We can compensate that with higher ISO or lower shutter speed.

ISO secondary effects

Let’s say we have the following picture (ISO 1600, 1/100s, f/3.5):

Night picture

That’s pretty dark huh? To get more light, keeping the depth field, we can either increase the ISO (the easy option) or reduce the shutter speed (not that difficult, but would require more stability to the camera since it’s night time). Let’s see what happens when we increase the ISO to 12800.

Night picture +ISO

Cool, we got a lighter picture, but with a noisy sky. Instead of increasing the ISO, if we decrease the shutter speed to 1/10 we get the following result.

Night picture -Speed

Pretty much similar, but without any noise.

Long exposure photography

You probably already saw those night pictures with car light trails. That’s possible if we slow down the shutter long enough to allow more light to enter, along with the trails of moving subjects like cars.

As you are slowing down the shutter speed, you will need to stabilise your camera so the picture does not have a shake effect. That’s normally done with a tripe. That’s an essencial piece for long exposure photography.

The following example was taken in above a high-way at night with a reduced shutter speed:

Light Trails


In this post we’ve seen the basics of the exposure triangle and how we can use aperture, shutter speed and ISO to impact our picture.

It’s important to take into consideration that we should be fully aware of these settings each time we take a picture so we understand them well.

There are a lot more to say about photography (automatic vs manual focus, whitebalance, etc). This post is a getting started for SLR cameras.

Happy photos.